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2015-04-14page_writeback: clean up mess around cancel_dirty_page()Konstantin Khlebnikov
This patch replaces cancel_dirty_page() with a helper function account_page_cleaned() which only updates counters. It's called from truncate_complete_page() and from try_to_free_buffers() (hack for ext3). Page is locked in both cases, page-lock protects against concurrent dirtiers: see commit 2d6d7f982846 ("mm: protect set_page_dirty() from ongoing truncation"). Delete_from_page_cache() shouldn't be called for dirty pages, they must be handled by caller (either written or truncated). This patch treats final dirty accounting fixup at the end of __delete_from_page_cache() as a debug check and adds WARN_ON_ONCE() around it. If something removes dirty pages without proper handling that might be a bug and unwritten data might be lost. Hugetlbfs has no dirty pages accounting, ClearPageDirty() is enough here. cancel_dirty_page() in nfs_wb_page_cancel() is redundant. This is helper for nfs_invalidate_page() and it's called only in case complete invalidation. The mess was started in v2.6.20 after commits 46d2277c796f ("Clean up and make try_to_free_buffers() not race with dirty pages") and 3e67c0987d75 ("truncate: clear page dirtiness before running try_to_free_buffers()") first was reverted right in v2.6.20 in commit ecdfc9787fe5 ("Resurrect 'try_to_free_buffers()' VM hackery"), second in v2.6.25 commit a2b345642f53 ("Fix dirty page accounting leak with ext3 data=journal"). Custom fixes were introduced between these points. NFS in v2.6.23, commit 1b3b4a1a2deb ("NFS: Fix a write request leak in nfs_invalidate_page()"). Kludge in __delete_from_page_cache() in v2.6.24, commit 3a6927906f1b ("Do dirty page accounting when removing a page from the page cache"). Since v2.6.25 all of them are redundant. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Cc: Tejun Heo <tj@kernel.org> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14mm: incorporate zero pages into transparent huge pagesEbru Akagunduz
This patch improves THP collapse rates, by allowing zero pages. Currently THP can collapse 4kB pages into a THP when there are up to khugepaged_max_ptes_none pte_none ptes in a 2MB range. This patch counts pte none and mapped zero pages with the same variable. The patch was tested with a program that allocates 800MB of memory, and performs interleaved reads and writes, in a pattern that causes some 2MB areas to first see read accesses, resulting in the zero pfn being mapped there. To simulate memory fragmentation at allocation time, I modified do_huge_pmd_anonymous_page to return VM_FAULT_FALLBACK for read faults. Without the patch, only %50 of the program was collapsed into THP and the percentage did not increase over time. With this patch after 10 minutes of waiting khugepaged had collapsed %99 of the program's memory. [aarcange@redhat.com: fix bogus BUG()] Signed-off-by: Ebru Akagunduz <ebru.akagunduz@gmail.com> Reviewed-by: Rik van Riel <riel@redhat.com> Reviewed-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: David Rientjes <rientjes@google.com> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14mm/compaction: enhance compaction finish conditionJoonsoo Kim
Compaction has anti fragmentation algorithm. It is that freepage should be more than pageblock order to finish the compaction if we don't find any freepage in requested migratetype buddy list. This is for mitigating fragmentation, but, there is a lack of migratetype consideration and it is too excessive compared to page allocator's anti fragmentation algorithm. Not considering migratetype would cause premature finish of compaction. For example, if allocation request is for unmovable migratetype, freepage with CMA migratetype doesn't help that allocation and compaction should not be stopped. But, current logic regards this situation as compaction is no longer needed, so finish the compaction. Secondly, condition is too excessive compared to page allocator's logic. We can steal freepage from other migratetype and change pageblock migratetype on more relaxed conditions in page allocator. This is designed to prevent fragmentation and we can use it here. Imposing hard constraint only to the compaction doesn't help much in this case since page allocator would cause fragmentation again. To solve these problems, this patch borrows anti fragmentation logic from page allocator. It will reduce premature compaction finish in some cases and reduce excessive compaction work. stress-highalloc test in mmtests with non movable order 7 allocation shows considerable increase of compaction success rate. Compaction success rate (Compaction success * 100 / Compaction stalls, %) 31.82 : 42.20 I tested it on non-reboot 5 runs stress-highalloc benchmark and found that there is no more degradation on allocation success rate than before. That roughly means that this patch doesn't result in more fragmentations. Vlastimil suggests additional idea that we only test for fallbacks when migration scanner has scanned a whole pageblock. It looked good for fragmentation because chance of stealing increase due to making more free pages in certain pageblock. So, I tested it, but, it results in decreased compaction success rate, roughly 38.00. I guess the reason that if system is low memory condition, watermark check could be failed due to not enough order 0 free page and so, sometimes, we can't reach a fallback check although migrate_pfn is aligned to pageblock_nr_pages. I can insert code to cope with this situation but it makes code more complicated so I don't include his idea at this patch. [akpm@linux-foundation.org: fix CONFIG_CMA=n build] Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Mel Gorman <mgorman@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14mm/page_alloc: factor out fallback freepage checkingJoonsoo Kim
This is preparation step to use page allocator's anti fragmentation logic in compaction. This patch just separates fallback freepage checking part from fallback freepage management part. Therefore, there is no functional change. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Mel Gorman <mgorman@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14mm/cma: change fallback behaviour for CMA freepageJoonsoo Kim
Freepage with MIGRATE_CMA can be used only for MIGRATE_MOVABLE and they should not be expanded to other migratetype buddy list to protect them from unmovable/reclaimable allocation. Implementing these requirements in __rmqueue_fallback(), that is, finding largest possible block of freepage has bad effect that high order freepage with MIGRATE_CMA are broken continually although there are suitable order CMA freepage. Reason is that they are not be expanded to other migratetype buddy list and next __rmqueue_fallback() invocation try to finds another largest block of freepage and break it again. So, MIGRATE_CMA fallback should be handled separately. This patch introduces __rmqueue_cma_fallback(), that just wrapper of __rmqueue_smallest() and call it before __rmqueue_fallback() if migratetype == MIGRATE_MOVABLE. This results in unintended behaviour change that MIGRATE_CMA freepage is always used first rather than other migratetype as movable allocation's fallback. But, as already mentioned above, MIGRATE_CMA can be used only for MIGRATE_MOVABLE, so it is better to use MIGRATE_CMA freepage first as much as possible. Otherwise, we needlessly take up precious freepages with other migratetype and increase chance of fragmentation. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Mel Gorman <mgorman@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14mm, hotplug: fix concurrent memory hot-add deadlockDavid Rientjes
There's a deadlock when concurrently hot-adding memory through the probe interface and switching a memory block from offline to online. When hot-adding memory via the probe interface, add_memory() first takes mem_hotplug_begin() and then device_lock() is later taken when registering the newly initialized memory block. This creates a lock dependency of (1) mem_hotplug.lock (2) dev->mutex. When switching a memory block from offline to online, dev->mutex is first grabbed in device_online() when the write(2) transitions an existing memory block from offline to online, and then online_pages() will take mem_hotplug_begin(). This creates a lock inversion between mem_hotplug.lock and dev->mutex. Vitaly reports that this deadlock can happen when kworker handling a probe event races with systemd-udevd switching a memory block's state. This patch requires the state transition to take mem_hotplug_begin() before dev->mutex. Hot-adding memory via the probe interface creates a memory block while holding mem_hotplug_begin(), there is no way to take dev->mutex first in this case. online_pages() and offline_pages() are only called when transitioning memory block state. We now require that mem_hotplug_begin() is taken before calling them -- this requires exporting the mem_hotplug_begin() and mem_hotplug_done() to generic code. In all hot-add and hot-remove cases, mem_hotplug_begin() is done prior to device_online(). This is all that is needed to avoid the deadlock. Signed-off-by: David Rientjes <rientjes@google.com> Reported-by: Vitaly Kuznetsov <vkuznets@redhat.com> Tested-by: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: Tang Chen <tangchen@cn.fujitsu.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Zhang Zhen <zhenzhang.zhang@huawei.com> Cc: Vladimir Davydov <vdavydov@parallels.com> Cc: Wang Nan <wangnan0@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14cma: debug: document new debugfs interfaceSasha Levin
Document the structure and files under the new debugfs interface. Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Laura Abbott <lauraa@codeaurora.org> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14mm-cma-allocation-trigger-fixAndrew Morton
s/CONFIG_CMA_ALIGNMENT/0/, per Joonsoo Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Laura Abbott <lauraa@codeaurora.org> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14mm: cma: release triggerSasha Levin
Provides a userspace interface to trigger a CMA release. Usage: echo [pages] > free This would provide testing/fuzzing access to the CMA release paths. [akpm@linux-foundation.org: coding-style fixes] [mhocko@suse.cz: fix build] Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Acked-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Laura Abbott <lauraa@codeaurora.org> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14mm: cma: allocation triggerSasha Levin
Provides a userspace interface to trigger a CMA allocation. Usage: echo [pages] > alloc This would provide testing/fuzzing access to the CMA allocation paths. Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Acked-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Laura Abbott <lauraa@codeaurora.org> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14mm: cma: debugfs interfaceSasha Levin
I've noticed that there is no interfaces exposed by CMA which would let me fuzz what's going on in there. This small patchset exposes some information out to userspace, plus adds the ability to trigger allocation and freeing from userspace. This patch (of 3): Implement a simple debugfs interface to expose information about CMA areas in the system. Useful for testing/sanity checks for CMA since it was impossible to previously retrieve this information in userspace. Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Acked-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Laura Abbott <lauraa@codeaurora.org> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14memory hotplug: use macro to switch between section and pfnSheng Yong
Use macro section_nr_to_pfn() to switch between section and pfn, instead of open-coding it. No semantic changes. Signed-off-by: Sheng Yong <shengyong1@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14mm: memcontrol: update copyright noticeJohannes Weiner
Add myself to the list of copyright holders. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14mm/memblock.c: rename local variable of memblock_type to `type'Baoquan He
A small cleanup. Seems in e3239ff9 ("memblock: Rename memblock_region to memblock_type and memblock_property to memblock_region") this one was missed. Signed-off-by: Baoquan He <bhe@redhat.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14mm: move mm_populate()-related code to mm/gup.cKirill A. Shutemov
It's odd that we have populate_vma_page_range() and __mm_populate() in mm/mlock.c. It's implementation of generic memory population and mlocking is one of possible side effect, if VM_LOCKED is set. __get_user_pages() is core of the implementation. Let's move the code into mm/gup.c. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: David Rientjes <rientjes@google.com> Cc: Michel Lespinasse <walken@google.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14mm: move gup() -> posix mlock() error conversion out of __mm_populateKirill A. Shutemov
This is praparation to moving mm_populate()-related code out of mm/mlock.c. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: David Rientjes <rientjes@google.com> Cc: Michel Lespinasse <walken@google.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14mm: rename __mlock_vma_pages_range() to populate_vma_page_range()Kirill A. Shutemov
__mlock_vma_pages_range() doesn't necessarily mlock pages. It depends on vma flags. The same codepath is used for MAP_POPULATE. Let's rename __mlock_vma_pages_range() to populate_vma_page_range(). This patch also drops mlock_vma_pages_range() references from documentation. It has gone in cea10a19b797 ("mm: directly use __mlock_vma_pages_range() in find_extend_vma()"). Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: David Rientjes <rientjes@google.com> Cc: Michel Lespinasse <walken@google.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14mm: rename FOLL_MLOCK to FOLL_POPULATEKirill A. Shutemov
After commit a1fde08c74e9 ("VM: skip the stack guard page lookup in get_user_pages only for mlock") FOLL_MLOCK has lost its original meaning: we don't necessarily mlock the page if the flags is set -- we also take VM_LOCKED into consideration. Since we use the same codepath for __mm_populate(), let's rename FOLL_MLOCK to FOLL_POPULATE. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: David Rientjes <rientjes@google.com> Cc: Michel Lespinasse <walken@google.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14slob: make slob_alloc_node() static and remove EXPORT_SYMBOL()Fabian Frederick
slob_alloc_node() is only used in slob.c. Remove the EXPORT_SYMBOL and make slob_alloc_node() static. Signed-off-by: Fabian Frederick <fabf@skynet.be> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14slub: use bool function return values of true/false not 1/0Joe Perches
Use the normal return values for bool functions Signed-off-by: Joe Perches <joe@perches.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Acked-by: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14mm, slab: correct config option in commentDavid Rientjes
CONFIG_SLAB_DEBUG doesn't exist, CONFIG_DEBUG_SLAB does. Signed-off-by: David Rientjes <rientjes@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14mm/slub.c: parse slub_debug O option in switch statementChris J Arges
By moving the O option detection into the switch statement, we allow this parameter to be combined with other options correctly. Previously options like slub_debug=OFZ would only detect the 'o' and use DEBUG_DEFAULT_FLAGS to fill in the rest of the flags. Signed-off-by: Chris J Arges <chris.j.arges@canonical.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Acked-by: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14mm/migrate: mark unmap_and_move() "noinline" to avoid ICE in gcc 4.7.3Geert Uytterhoeven
With gcc version 4.7.3 (Ubuntu/Linaro 4.7.3-12ubuntu1) : mm/migrate.c: In function `migrate_pages': mm/migrate.c:1148:1: internal compiler error: in push_minipool_fix, at config/arm/arm.c:13500 Please submit a full bug report, with preprocessed source if appropriate. See <file:///usr/share/doc/gcc-4.7/README.Bugs> for instructions. Preprocessed source stored into /tmp/ccPoM1tr.out file, please attach this to your bugreport. make[1]: *** [mm/migrate.o] Error 1 make: *** [mm/migrate.o] Error 2 Mark unmap_and_move() (which is used in a single place only) "noinline" to work around this compiler bug. [akpm@linux-foundation.org: make it conditional on gcc-4.7.3 and arm] [khilman@kernel.org: fine-tune compiler versions] [akpm@linux-foundation.org: fix comment] Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Reported-by: Kevin Hilman <khilman@kernel.org> Cc: Marc Zyngier <marc.zyngier@arm.com> Tested-by: Kevin Hilman <khilman@linaro.org> Tested-by: Lina Iyer <lina.iyer@linaro.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14watchdog: introduce the hardlockup_detector_disable() functionUlrich Obergfell
Have kvm_guest_init() use hardlockup_detector_disable() instead of watchdog_enable_hardlockup_detector(false). Remove the watchdog_hardlockup_detector_is_enabled() and the watchdog_enable_hardlockup_detector() function which are no longer needed. Signed-off-by: Ulrich Obergfell <uobergfe@redhat.com> Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14watchdog: clean up some function names and argumentsUlrich Obergfell
Rename the update_timers*() functions to update_watchdog*(). Remove the boolean argument from watchdog_enable_all_cpus() because update_watchdog_all_cpus() is now a generic function to change the run state of the lockup detectors and to have the lockup detectors use a new sample period. Signed-off-by: Ulrich Obergfell <uobergfe@redhat.com> Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14watchdog: enable the new user interface of the watchdog mechanismUlrich Obergfell
With the current user interface of the watchdog mechanism it is only possible to disable or enable both lockup detectors at the same time. This series introduces new kernel parameters and changes the semantics of some existing kernel parameters, so that the hard lockup detector and the soft lockup detector can be disabled or enabled individually. With this series applied, the user interface is as follows. - parameters in /proc/sys/kernel . soft_watchdog This is a new parameter to control and examine the run state of the soft lockup detector. . nmi_watchdog The semantics of this parameter have changed. It can now be used to control and examine the run state of the hard lockup detector. . watchdog This parameter is still available to control the run state of both lockup detectors at the same time. If this parameter is examined, it shows the logical OR of soft_watchdog and nmi_watchdog. . watchdog_thresh The semantics of this parameter are not affected by the patch. - kernel command line parameters . nosoftlockup The semantics of this parameter have changed. It can now be used to disable the soft lockup detector at boot time. . nmi_watchdog=0 or nmi_watchdog=1 Disable or enable the hard lockup detector at boot time. The patch introduces '=1' as a new option. . nowatchdog The semantics of this parameter are not affected by the patch. It is still available to disable both lockup detectors at boot time. Also, remove the proc_dowatchdog() function which is no longer needed. [dzickus@redhat.com: wrote changelog] [dzickus@redhat.com: update documentation for kernel params and sysctl] Signed-off-by: Ulrich Obergfell <uobergfe@redhat.com> Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14watchdog: implement error handling for failure to set up hardware perf eventsUlrich Obergfell
If watchdog_nmi_enable() fails to set up the hardware perf event of one CPU, the entire hard lockup detector is deemed unreliable. Hence, disable the hard lockup detector and shut down the hardware perf events on all CPUs. [dzickus@redhat.com: update comments to explain some code] Signed-off-by: Ulrich Obergfell <uobergfe@redhat.com> Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14watchdog: introduce separate handlers for parameters in /proc/sys/kernelUlrich Obergfell
Separate handlers for each watchdog parameter in /proc/sys/kernel replace the proc_dowatchdog() function. Three of those handlers merely call proc_watchdog_common() with one different argument. Signed-off-by: Ulrich Obergfell <uobergfe@redhat.com> Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14watchdog: introduce proc_watchdog_common()Ulrich Obergfell
Three of four handlers for the watchdog parameters in /proc/sys/kernel essentially have to do the same thing. if the parameter is being read { return the state of the corresponding bit(s) in 'watchdog_enabled' } else { set/clear the state of the corresponding bit(s) in 'watchdog_enabled' update the run state of the lockup detector(s) } Hence, introduce a common function that can be called by those handlers. The callers pass a 'bit mask' to this function to indicate which bit(s) should be set/cleared in 'watchdog_enabled'. This function handles an uncommon race with watchdog_nmi_enable() where a concurrent update of 'watchdog_enabled' is possible. We use 'cmpxchg' to detect the concurrency. [This avoids introducing a new spinlock or a mutex to synchronize updates of 'watchdog_enabled'. Using the same lock or mutex in watchdog thread context and in system call context needs to be considered carefully because it can make the code prone to deadlock situations in connection with parking/unparking the watchdog threads.] Signed-off-by: Ulrich Obergfell <uobergfe@redhat.com> Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14watchdog: move definition of 'watchdog_proc_mutex' outside of proc_dowatchdog()Ulrich Obergfell
This series removes proc_dowatchdog(). Since multiple new functions need the 'watchdog_proc_mutex' to serialize access to the watchdog parameters in /proc/sys/kernel, move the mutex outside of any function. Signed-off-by: Ulrich Obergfell <uobergfe@redhat.com> Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14watchdog: introduce the proc_watchdog_update() functionUlrich Obergfell
This series introduces a separate handler for each watchdog parameter in /proc/sys/kernel. The separate handlers need a common function that they can call to update the run state of the lockup detectors, or to have the lockup detectors use a new sample period. Signed-off-by: Ulrich Obergfell <uobergfe@redhat.com> Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14watchdog: new definitions and variables, initializationUlrich Obergfell
The hardlockup and softockup had always been tied together. Due to the request of KVM folks, they had a need to have one enabled but not the other. Internally rework the code to split things apart more cleanly. There is a bunch of churn here, but the end result should be code that should be easier to maintain and fix without knowing the internals of what is going on. This patch (of 9): Introduce new definitions and variables to separate the user interface in /proc/sys/kernel from the internal run state of the lockup detectors. The internal run state is represented by two bits in a new variable that is named 'watchdog_enabled'. This helps simplify the code, for example: - In order to check if any of the two lockup detectors is enabled, it is sufficient to check if 'watchdog_enabled' is not zero. - In order to enable/disable one or both lockup detectors, it is sufficient to set/clear one or both bits in 'watchdog_enabled'. - Concurrent updates of 'watchdog_enabled' need not be synchronized via a spinlock or a mutex. Updates can either be atomic or concurrency can be detected by using 'cmpxchg'. Signed-off-by: Ulrich Obergfell <uobergfe@redhat.com> Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14ocfs2: make mlog_errno return the errnoAndrew Morton
ocfs2 does mlog_errno(v); return v; in many places. Change mlog_errno() so we can do return mlog_errno(v); For some weird reason this patch reduces the size of ocfs2 by 6k: akpm3:/usr/src/25> size fs/ocfs2/ocfs2.ko text data bss dec hex filename 1146613 82767 832192 2061572 1f7504 fs/ocfs2/ocfs2.ko-before 1140857 82767 832192 2055816 1f5e88 fs/ocfs2/ocfs2.ko-after [dan.carpenter@oracle.com: double evaluation concerns in mlog_errno()] Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: alex chen <alex.chen@huawei.com> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14ocfs2: check if the ocfs2 lock resource has been initialized before calling ↵alex chen
ocfs2_dlm_lock If ocfs2 lockres has not been initialized before calling ocfs2_dlm_lock, the lock won't be dropped and then will lead umount hung. The case is described below: ocfs2_mknod ocfs2_mknod_locked __ocfs2_mknod_locked ocfs2_journal_access_di Failed because of -ENOMEM or other reasons, the inode lockres has not been initialized yet. iput(inode) ocfs2_evict_inode ocfs2_delete_inode ocfs2_inode_lock ocfs2_inode_lock_full_nested __ocfs2_cluster_lock Succeeds and allocates a new dlm lockres. ocfs2_clear_inode ocfs2_open_unlock ocfs2_drop_inode_locks ocfs2_drop_lock Since lockres has not been initialized, the lock can't be dropped and the lockres can't be migrated, thus umount will hang forever. Signed-off-by: Alex Chen <alex.chen@huawei.com> Reviewed-by: Joseph Qi <joseph.qi@huawei.com> Reviewed-by: joyce.xue <xuejiufei@huawei.com> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14ocfs2: logging: remove static buffer, use vsprintf extension %pVJoe Perches
Use the vsprintf %pV extension to avoid using a static buffer and remove the now unnecessary buffer. Signed-off-by: Joe Perches <joe@perches.com> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14ocfs2: incorrect check for debugfs returnsChengyu Song
debugfs_create_dir and debugfs_create_file may return -ENODEV when debugfs is not configured, so the return value should be checked against ERROR_VALUE as well, otherwise the later dereference of the dentry pointer would crash the kernel. This patch tries to solve this problem by fixing certain checks. However, I have that found other call sites are protected by #ifdef CONFIG_DEBUG_FS. In current implementation, if CONFIG_DEBUG_FS is defined, then the above two functions will never return any ERROR_VALUE. So another possibility to fix this is to surround all the buggy checks/functions with the same #ifdef CONFIG_DEBUG_FS. But I'm not sure if this would break any functionality, as only OCFS2_FS_STATS declares dependency on DEBUG_FS. Signed-off-by: Chengyu Song <csong84@gatech.edu> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14ocfs2: fix a typo in the copyright statementJakub Wilk
Signed-off-by: Jakub Wilk <jwilk@jwilk.net> Reviewed-by: Eric Ren <zren@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14ocfs2: fix possible uninitialized variable accessJoseph Qi
In ocfs2_local_alloc_find_clear_bits and ocfs2_get_dentry, variable numfound and set may be uninitialized and then used in tracepoint. In ocfs2_xattr_block_get and ocfs2_delete_xattr_in_bucket, variable block_off and xv may be uninitialized and then used in the following logic due to unchecked return value. This patch fixes these possible issues. Signed-off-by: Joseph Qi <joseph.qi@huawei.com> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14ocfs2: remove goto statement in ocfs2_check_dir_for_entry()Daeseok Youn
Signed-off-by: Daeseok Youn <daeseok.youn@gmail.com> Reviewed-by: Joseph Qi <joseph.qi@huawei.com> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14ocfs2: rollback the cleared bits if error occurs after ↵Joseph Qi
ocfs2_block_group_clear_bits ocfs2_block_group_clear_bits will clear bits in block group bitmap. Once it succeeds but fails in the following step, it will cause block group bitmap mismatch the corresponding count recorded in dinode. So rollback the cleared bits if error occurs. Signed-off-by: Joseph Qi <joseph.qi@huawei.com> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14ocfs2: use ENOENT instead of EEXIST when get system file failsJoseph Qi
When ocfs2_get_system_file_inode fails, it is obscure to set the return value to -EEXIST. So change it to -ENOENT. Signed-off-by: Joseph Qi <joseph.qi@huawei.com> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14ocfs2: use actual name length when find entry in ocfs2_orphan_del()Joseph Qi
If the namelen is 20 and name only has actual length 16, it will fail in ocfs2_find_entry because of mismatch. So use actual name length when find entry. Signed-off-by: Joseph Qi <joseph.qi@huawei.com> Signed-off-by: Yiwen Jiang <jiangyiwen@huawei.com> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14ocfs2: dereferencing freed pointers in ocfs2_reflink()Dan Carpenter
The code at the "out" label assumes that "default_acl" and "acl" are NULL, but actually the pointers can be NULL, unitialized, or freed. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Reviewed-by: Mark Fasheh <mfasheh@suse.de> Cc: Joel Becker <jlbec@evilplan.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14ocfs2: fix typo in ocfs2_reserve_local_alloc_bitsJoseph Qi
In ocfs2_reserve_local_alloc_bits, it calls ocfs2_error if local alloc inode bitmap used bits mismatch, but the log mistakes it as free bits. Signed-off-by: Joseph Qi <joseph.qi@huawei.com> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14ocfs2: do not use ocfs2_zero_extend during direct IOJoseph Qi
In ocfs2_direct_IO_write, we use ocfs2_zero_extend to zero allocated clusters in case of cluster not aligned. But ocfs2_zero_extend uses page cache, this may happen that it clears the data which blockdev_direct_IO has already written. We should use blkdev_issue_zeroout instead of ocfs2_zero_extend during direct IO. So fix this issue by introducing ocfs2_direct_IO_zero_extend and ocfs2_direct_IO_extend_no_holes. Reported-by: Yiwen Jiang <jiangyiwen@huawei.com> Signed-off-by: Joseph Qi <joseph.qi@huawei.com> Tested-by: Yiwen Jiang <jiangyiwen@huawei.com> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14ocfs2: take inode lock when get clustersJoseph Qi
We need take inode lock when calling ocfs2_get_clusters. And use GFP_NOFS instead of GFP_KERNEL. Signed-off-by: Joseph Qi <joseph.qi@huawei.com> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14ocfs2: no need get dinode bh when zeroing extendJoseph Qi
Since di_bh won't be used when zeroing extend, set it to NULL. Signed-off-by: Joseph Qi <joseph.qi@huawei.com> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14ocfs2: fix a typing error in ocfs2_direct_IO_writeJoseph Qi
Only when direct IO succeeds we need consider zeroing out in case of cluster not aligned. Signed-off-by: Joseph Qi <joseph.qi@huawei.com> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14ocfs2: avoid a pointless delay in o2cb_cluster_check()Daeseok Youn
Fix an off-by-one when attempting to avoid an msleep() on the final loop iteration. Signed-off-by: Daeseok Youn <daeseok.youn@gmail.com> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14ocfs2: one function call less in user_cluster_connect() after error detectionMarkus Elfring
kfree() was called by user_cluster_connect() even if a previous call of the kzalloc() function failed. Return from this implementation directly after failure detection. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>